Those people become experts - they get incredibly attuned - at navigating risks when it comes to getting fired. It's like people that don't work hard consistently, and then cram as much in at the last second right before getting in trouble. They develop an almost sixth-sense like ability to know when they have to do something, and then they do just enough. A lot of times in my observation, persistently unmotivated people don't know what they want, either out of work or life in general; so it does them little good to quit and go find a job they want to do, because they have no idea what they want to do.

It's the classic rhetorical: why not just work consistently, and not have to worry about cramming? Why do people behave that way (in either school or work)? In my personal experience, I've found the only time I cram, is when I'm stuck doing something I really don't care about (happened constantly in school).